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At least 1,351 records · Page 75Linked to original sources
USGS1973

Index to water-quality data available from the U.S. Geological Survey in machine-readable form to December 31, 1972; Northeastern region

This report lists water quality stations operated by the U.S. Geological Survey for which data are available in machine-readable form. The data are the results of analyses of water samples and indicate the chemical and physical characteristics of surface and ground water. Samples of surface water were collected at designated sites at predetermined intervals such as once daily, weekly, monthly, or less frequently. Samples of ground water were collected from wells infrequently and on an irregular basis.

Water-Resources Investigations Report↗
USGS1973

Index to water-quality data available from the U.S. Geological Survey in machine-readable form to December 31, 1972: Southeastern Region

This report lists water quality stations operated by the Geological Survey for what data are available in machine-readable form. The data are the results of analyses of water samples and indicate the chemical and physical characteristics of surface and ground water. The stations are listed according to station number within each State. The water quality data are identified by 5-digit parameter codes and are grouped into twenty-one parameter categories. The analytical results for all samples in any one year are then grouped within the parameter categories. The report lists the available retrieval options, the machine-readable output options user charges, and how to obtain the data.

Water-Resources Investigations Report↗
USGS1982

Water-quality characteristics of Everglades National Park, 1959-77, with reference to the effects of water management

The U.S. Geological Survey has collected water-quality data in the Everglades National Park since 1959. Major ions, macronutrients, trace elements, and pesticides are the primary chemical groups analyzed. The period of record and frequency of sampling vary for each chemical group, with the longest record for the major ions and the shortest for the macronutrients. Within the park there are three major drainageways: Big Cypress Swamp, Shark River Slough, and Taylor Slough. Each drainageway exhibits unique hydrologic conditions, yet there is a high degree of homogeneity in water-quality characteristics among these areas. Seasonal changes in major-ion, trace-element, and macronutrient concentrations are marked in the shallow marsh. Concentrations generally increase in the dry season due to evapotranspiration, changes in chemical equilibria, and precipitation. Water-management practices in south Florida have changed the water quality in the Shark River Slough. Most major-ion, dissolved-solid, and iron concentrations and color levels have steadily increased since 1963. The water quality in the other two drainageways has not changed since sampling began. Chlorinated-hydrocarbon insecticide residues in bottom material were found in low concentration at every sampling station in the park. (USGS)

Florida↗
USGS2006

Deep Europe today: Geophysical synthesis of the upper mantle structure and lithospheric processes over 3.5 Ga

We present a summary of geophysical models of the subcrustal lithosphere of Europe. This includes the results from seismic (reflection and refraction profiles, P- and S-wave tomography, mantle anisotropy), gravity, thermal, electromagnetic, elastic and petrological studies of the lithospheric mantle. We discuss major tectonic processes as reflected in the lithospheric structure of Europe, from Precambrian terrane accretion and subduction to Phanerozoic rifting, volcanism, subduction and continent-continent collision. The differences in the lithospheric structure of Precambrian and Phanerozoic Europe, as illustrated by a comparative analysis of different geophysical data, are shown to have both a compositional and a thermal origin. We propose an integrated model of physical properties of the European subcrustal lithosphere, with emphasis on the depth intervals around 150 and 250 km. At these depths, seismic velocity models, constrained by body-and surface-wave continent-scale tomography, are compared with mantle temperatures and mantle gravity anomalies. This comparison provides a framework for discussion of the physical or chemical origin of the major lithospheric anomalies and their relation to large-scale tectonic processes, which have formed the present lithosphere of Europe. ?? The Geological Society of London 2006.

Geological Society Memoir↗
USGS1989

The geology, botany and chemistry of selected peat-forming environments from temperate and tropical latitudes

Peat has been studied in several geologic settings: (1) glaciated terrain in cold temperate Maine and Minnesota, U.S.A.; (2) an island in the Atlantic Ocean off the coast of Maine, where sea level is rising; (3) the warm temperate U.S. Atlantic and Gulf Coastal Plains, where sea level has changed often; and (4) the tropical coast of Sarawak, Malaysia, and the tropical delta of the Batang Hari River, Sumatra, Indonesia. Most of these deposits are domed (ombrotrophic or partly ombrotrophic) bogs in which peat accumulation continued above the surface of the surrounding soil. However, the bogs of the U.S. Atlantic and Gulf Coastal Plains are comparatively not as domed, and many have almost level surfaces. In some bogs, aquatic or semi-aquatic plant materials accumulated, replaced water in the depressions, and formed a surface on which marsh or swamp vegetation could subsequently live, die, and accumulate. In others, the plant materials accumulated initially on level silt or sand surfaces supporting marshes or swamps. As the peat dome formed, plants growing on it changed from luxuriant ones near the base of the dome, where nutrients were brought into the bog by surface and ground water, to stunted ones at the top of the dome, where the raised bogs are fed by nutrient-poor precipitation. The physical and chemical changes that take place in the sequence of environments from the pond stage of deposit development, through the grassy marsh stage, through the forested swamp stage, and finally through the heath dome stage can be measured in terms of acidity and ash, volatile matter, carbon, hydrogen, nitrogen, sulfur and oxygen contents, as well as in the kind and distribution of trace elements. The organic and inorganic contents of the deposits relate to geomorphology, and geomorphology relates to their settings. As models of coal formation, some domed peat deposits may help in solving problems of distribution and character of ancient coal beds. But clearly not all peat deposits are precursors of coal. Most Holocene peat deposits are subject to destruction by erosion, fire and decomposition through microbial and chemical oxidation before burial. The best environments for coal precursors have biomass accumulation, a continuously rising water table within the mass, and minimum influx of clay and silt until preservation by burial. The most suitable settings for future economic coal deposits are domed bogs that accumulate thick, widespread peat having low ash and low sulfur contents. The ombrotrophic peat deposits of tropical Sarawak and Sumatra are thick and extensive, contain low-ash and low-sulfur peat, and have high heating values. They are considered to be the best tropical coal analogs because of their extent and chances of preservation; the base of the peat is below adjacent river levels, and chemical and structural conditions are favorable for accumulation.

International Journal of Coal Geology↗
USGS2001

Ground-water flow to Death Valley, as inferred from the chemistry and geohydrology of selected springs in Death Valley National Park, California and Nevada

Death Valley lies downgradient from adjacent valleys to the north, south, east, and west in California and Nevada, and is the site of substantial ground-water discharge. The sources of the discharging waters have been discussed by several investigators in the past and are of heightened concern because of the potential disposal of high-level radioactive waste at Yucca Mountain, Nevada, and because of ground-water withdrawals attendant to commercial mining in the northwestern Amargosa Valley region. This report describes high- and low-discharge springs in and along the Amargosa Range that were sampled to augment the level of understanding of the extent and distribution of westward ground-water flow through the range. The Black Mountains do not seem to be part of a significant path of ground-water flow from the Amargosa region. This is attributed to the complex lithology and geologic history of the Black Mountains structural block and to the presence of the intervening Furnace Creek fault zone. The only ground-water discharge associated with the Black Mountains where water chemistry reflects an external source or sources is Saratoga Spring, for which δ 2 H and δ 18 O data indicate recharge in the Spring Mountains to the east. The southern part of the Funeral Mountains transmits a large volume of water through faulted and fractured rocks of Cambrian age that lie at or along the distal part of the northeast -oriented Spotted Range-Mine Mountain structural zone. Waters discharging from springs in the Furnace Creek Ranch vicinity (Travertine and Nevares) both compositionally and isotopically resemble waters from the Ash Meadows spring group in the Amargosa Desert. The Ash Meadows springs and water in the Amargosa Valley alluvium likely are chemically representative of ground water entering the southern Funeral Mountains. Much less ground water flows through the central and northern Funeral Mountains than flows through the southern part, as indicated by the geologic setting and chemistry of Keane Wonder Spring. The northern one-half of the mountains comprises early-to-middle Proterozoic metamorphic rocks that are the core of the Funeral Mountains anticlinorium. The core is largely unfaulted, plunges to the northeast and southwest, and is truncated to some extent on the east by the shallow-dipping Boundary Canyon fault. This structural setting and the paucity of springs in the northern one-half of the Funeral Mountains indicate a long traveltime from the Amargosa region to the western margin of the northern and central parts of the mountains. The Grapevine Mountains include the highest elevations in the Amargosa Range. Substantial precipitation and recharge above about 2,000 meters are evinced by numerous small springs and seeps along the east and west margins. The local nature of the recharge is reflected in δ 2 H and δ 18 O values and in the spring chemistries that indicate control by Tertiary volcanic rocks. The highest spring discharges associated with the Grapevine Mountains are near the north end of the mountains in the Grapevine Ranch area. The springs in this area are similar chemically and isotopically, except for one or two order-of-magnitude differences in calcium, magnesium, and strontium concentrations and a 1.2 per mil difference in δ 13 C values. These differences can be attributed to differences in the distal parts of the respective flow paths. The springs also lie at the end of a northeast -oriented structural zone in the Walker Lane Belt, and their δ 2 H, δ 13 C, and δ 18 O values indicate a recharge area likely to the northeast, outside of the Grapevine Mountains.

California;Nevada↗
USGS2024

Geologic sources and well integrity impact methane emissions from orphaned and abandoned oil and gas wells

The 160-year history of oil and gas drilling in the United States has left a legacy of unplugged orphaned and abandoned wells, some of which are leaking methane and other hazardous chemicals into the environment. The locations of around 120,000 documented orphaned wells are currently known with the number of undocumented orphaned wells possibly ranging towards a million. The bulk of methane emissions originate from only 10 % of orphaned and abandoned wells, while the remaining wells have undetectable emissions. Understanding the sources of methane emissions from orphaned wells is key to estimating emission rates and prioritizing plugging. In this article, we identify key studies reporting methane emission measurements from orphaned and abandoned wells in the published literature and analyze previously published isotopic methane data to categorize the sources of methane emissions. Three primary geologic sources provide methane to a leaking well that can migrate from geologic formations into or along the wellbore to contaminate groundwater, the surface environment, and the atmosphere. These geologic sources of methane are petroleum (oil and gas) sourced reservoirs, coal seams, and methanogenesis occurring in and around the wellbore. Thermogenic petroleum gas reservoirs are associated with the highest emission rates measured to date. The next highest rates are from coalbed methane sources, while biogenic sources are the lowest based on the publicly available measured emissions data. Well conditions that could potentially enable methane transport include decay of the wellhead and surface infrastructure, wellbore deterioration from corrosive fluids in the subsurface, delamination of the casing and cement, damage from seismicity, and new fracture networks created by hydraulic fracturing of newly drilled neighboring wells. With an understanding of these geologic sources and well conditions, we can (1) better identify areas where high-emitting wells are likely to be present, (2) improve emission rate estimates from orphaned and abandoned wells, and (3) better prioritize wells for plugging.

Science of the Total Environment↗
USGS1992

Applying the DRASTIC model: A review of county-scale maps

The potential for contamination of ground water has become an issue of great concern to citizens and government alike, especially in the last decade. Numerous methods for assessing ground water vulnerability to contamination have been proposed and used. These methods include field-scale deterministic models that predict the rate of migration and fate of specific chemicals, and regional models that attempt to show general trends of ground-water vulnerability to contamination. To address regional ground-water vulnerability, a model may focus on characteristics of the soil, the geologic materials at and above the unconfined water table, or on the larger part of the geologic framework containing aquifers. A model's focus significantly affects the characteristics and, therefore, the utility of maps produced by the model. For example, a model focusing on the soil or vadose zone cannot adequately characterize the contamination potential of confined aquifers. The most commonly-used method for regional assessment of ground-water vulnerability is called "DRASTIC," an acronym for the seven factors that comprise the model. The U.S. Environmental Protection Agency (EPA) funded the development of the DRASTIC model, and used it as an assessment tool in their National Pesticide Survey (USEPA, 1992). In that Survey and in other assessments of contamination potential from application of agricultural chemicals, the pesticide version of DRASTIC is used; it differs from the standard DRASTIC model only in the degree of weighting applied to the seven factors. The DRASTIC model was developed by a committee of technical advisors who used the consensus approach to specify the relative significance of each factor. DRASTIC was designed primarily as a regional tool for prioritization, or screening, to indicate those areas (of at least 100 acres in size) which are generally more sensitive to contamination and, therefore, in need of more detailed mapping and evaluation or monitoring. The committee also intended DRASTIC to support decisions on allocation of scarce monitoring or remediation resources, and to serve as an educational tool. A detailed user's manual for the DRASTIC model (Aller and others, 1987) provides descriptions of common hydrogeologic settings across the United States and expected values for the seven factors; with this information and a specified "weight" or multiplier applied to each factor, DRASTIC scores can be calculated for each setting, and a map of these DRASTIC scores generated. The authors of this model intended it to be sufficiently objective and straightforward that it could be effectively used by persons with but a rudimentary knowledge of hydrogeologic principles. By adjusting the factor values for actual or interpreted local conditions a more knowledgeable person should be able to produce a somewhat more realistic and, therefore, reliable map of ground water vulnerability than by using the expected values for a given hydrogeologic setting. Other models for evaluating regional ground-water vulnerability have been developed; of importance to this report are models developed by the Illinois State Geological Survey (ISGS), the Wisconsin Department of Natural Resources (WDNR), and a joint effort between the U.S. Geological Survey (USGS) and the ISGS. All of these models, as well as DRASTIC, can only estimate the relative potential for contamination, either with a numerical scheme or a hierarchy of contamination potential map units. The model developed by WDNR (Schmidt, 1987) is based on a numerical scheme. It was used to generate a statewide contamination susceptibility map of Wisconsin (Schmidt and Kessler, 1987); Schmidt (1987) defines ground water contamination susceptibility as the "ease with which water (and, presumably, accompanying contaminants) at the surface can reach the water table." The model is not limited to aquifers, but rather considers all unconfined ground water whether in sandy surface aquifers or low-permeability glacial till. Ground water in confined aquifers is not addressed. Contamination susceptibility is estimated by a factor-weighting scheme similar in concept to DRASTIC. The factors (soil texture, surficial deposits, depth to the water table, bedrock type, and glacial drift thickness) are assigned an arbitrary value based on perceived importance. These numbers are then weighted and summed to produce the contamination susceptibility score. This model is compared and contrasted with other models elsewhere in this report. In contrast, the ISGS method avoids the use of a numerical system to rate the relative potential for contamination, and instead orders the map units in a hierarchy from relatively low to relatively high contamination potential. Also in contrast to the two models described above, the ISGS model relies solely on the textural character of the geologic framework to a specified depth. For example, a statewide map (Berg and others, 1984, scale 1:500,000) addresses land burial of wastes, and shows the contamination potential of aquifers within geologic units in the upper 50 feet. Another ISGS map (Keefer and Berg, 1990) addresses the contamination of major, economically important aquifers, and therefore evaluates contamination potential to greater depths (to greater than 300 feet). In general, the ISGS contamination potential maps evaluate aquifers, and do not evaluate potential for contamination of ground water at the unconfined water table in geologic units that are not aquifers (for example, in glacial till or finegrained lake sediments). With the cooperation of the ISGS, I have developed a model (Seller and Berg, in press) for the regional assessment of aquifer contamination potential that is based on ISGS techniques, adapted to a broader map area where detailed information may be unavailable. This model was used to generate a map of aquifer contamination potential for an area encompassing parts of five states near southern Lake Michigan and Lake Erie; the model and map are currently being refined and evaluated.

Open-File Report↗
USGS2008

Occurrence of transformation products in the environment

Historically, most environmental occurrence research has focused on the parent compounds of organic contaminants. Research, however, has documented that the environmental transport of chemicals, such as pesticides and emerging contaminants, are substantially underestimated if transformation products are not considered. Although most examples described herein were drawn from research conducted by the U.S. Geological Survey, such results are generally reflective of those found in other parts of the world. Results from a study of 51 streams in the Midwestern United States found that transformation products were seven of the ten most frequently detected pesticide compounds in late spring runoff (after application of pre-emergent herbicides), and nine of the ten most frequently detected compounds in fall season runoff (during and after harvest). In fact, 70% of the total herbicide concentration in water from the Mississippi River Basin was from transformation products. Results from a study of 86 municipal wells in Iowa found the frequency of detection increased from 17%, when pesticide parent compounds were considered, to 53%, when both parents and transformation products were considered. Transformation products were 12 of the 15 most frequently detected compounds for this groundwater study. Although studies on transformation products of synthetic organic compounds other than pesticides are not as common, wastewater treatment plant discharges have repeatedly been shown to contribute such transformation products to streams. In addition, select detergent transformation products have been commonly found in solid waste in the 1000's mg/kg. These findings and many others document that transformation products must be considered to fully assess the potential environmental occurrence of chemical contaminants and their transport and fate in various compartments of the hydrologic system. ?? 2008 Springer-Verlag Berlin Heidelberg.

The Handbook of Environmental Chemistry series↗
USGS1984

National water summary 1983: Hydrologic events and issues

The United States as a Nation possesses abundant water resources and has developed and used those resources extensively. The national renewable supply of water is about 1,400 billion gallons per day (for the conterminous 48 States). Approximately 380 billion gallons per day of freshwater is withdrawn for use by the Nation's homes, farms, and industries, and about 280 billion gallons per day is returned to streams. Although a large percentage of the Nation's waste is carried in this return flow, the quality of water in streams has improved in many respects as a result of the pollution-control pro- grams of recent years. However, much remains to be learned about water quality particularly the extent of contamination by synthetic organic chemicals and heavy metals, and the effects of these contaminants on human health.

Water Supply Paper↗
USGS1901

Twenty-First Annual report of the Director of the United States Geological Survey, 1899-1900: Part VII - Texas

Area treated. —The Black and Grand prairies of Texas and southern Indian Territory comprise about 50,000 square miles (see Pl. LXV, in pocket)—an area equal to that of fifty of the quadrangles mapped and described by the United States Geological Survey in its Geologic Atlas of the United States. The accompanying general geologic map (Pl. LXVI, in pocket) is a condensed presentation of the geology usually shown on that number of atlas sheets as published in folio form. Most of these quadrangles have been studied by the writer and his former assistants. Sources of data. —An entirely satisfactory presentation of these results is still impossible by reason of the lack of adequate maps. The topographic maps of the United States Geological Survey, which cover 24 of the 50 units of area, were made in the earlier years of the Survey and with a contour interval insufficient for the expression of the geology. For the remaining portion of the area it was necessary to use as a base the Land Office maps of the State of Texas. The conclusions herein presented, often condensed in a short paragraph, are founded upon a large amount of paleontologic, stratigraphic, and topographic data. The results, so far as they refer to the Black and Grand prairies, are the outcome of studies made by the writer since 1882, sometimes independently, sometimes with the assistance of the United States Geological Survey, and during two years in connection with the Texas Geological Survey. In times past he has been assisted in this work by his former students, C. C. McCulloch, now captain, U. S. A.; Messrs. Wilson T. Davidson and L. T. Dashiel; Mr. Joseph A. Taff, now of the United States Geological Survey; Dr. J. W. Stone, Mr. N. F. Drake, and Mr. G. H. Ragsdale. Inasmuch as the details which these gentlemem worked out were problems of the writer's suggestion, he has incorporated them into this paper, and here acknowledges indebtedness therefor. Upon the writer's retirement from the Texas Survey, Mr. Taff continued the work of mapping the region. He published two reports, which have been freely used and which have been of great assistance in the preparation of this paper. Importance of paleontology. —In addition to the collection of the data which appear in the text and illustrations, much paleontologic research has been necessary in order to classify the formations. Paleontology is the most reliable guide in determining the position of any bed in the geologic series with a view to ascertaining the depth, from any particular portion of the surface, of the underground waters in the Cretaceous regions of Texas. If a few species of fossils, such as can be found in any locality, be sent to one familiar with the sequence of the beds, he can predict within a few feet the depth below the surface of any particular water-bearing stratum in the series. It was a labor of years to disentangle the preexisting confusion concerning the occurrence and succession of these fossils and their bearings upon the determination and definition of the strata. Their further consideration has been left to Mr. T. W. Stanton, who, it is presumed, will make final publication of the descriptions and the scientific results. This is not a final and complete report. Detailed field work is desirable in many localities. Chemical analyses of water and illustrations of typical scenery should be more complete, but these were not obtainable with the means and time at the writer's disposal. When appreciation of geologic investigation shall have been awakened in Texas and the region under discussion shall have been studied more closely by resident students, in the manner now common in other parts of the United States, the data here presented will be largely increased and refined, and the conclusions will doubtless be correspondingly amended and rectified.

Texas↗
USGS1973

Water resources data for West Virginia, water year 1972

Water resources data for the 1972 water year for West Virginia including records of streamflow or reservoir storage at gaging stations, partial-record stations, and miscellaneous sites, and records of water-quality data on the chemical and physical characteristics of surface water, are given in this report. In Part 1, records are included for 126 gaging stations of which 119 are streamflow discharge stations, 1 is stage only streamflow station, and 6 are reservoir or lake stations; also included are records for 7 low-flow partial record stations, 42 crest-stage partial-record stations, and 12 miscellaneous sites. Locations of gaging stations are shown in Figure 1. In Part 2, data on the quality of surface water (chemical, temperature, and sediment) were collected from designated sampling sites at predetermined intervals, such as once daily, weekly, monthly, or less frequently, and at some sites data were recorded on punched paper tape at 15-, 30-, or 60-minute intervals. Records are given for 30 sampling stations of which 18 are continuous record stations, and 12 are partial-record stations. Locations of water-quality stations are shown in Figure 1. A few pertinent stations (not included above) in bordering States are also included in this report. The records were collected and computed by the Water Resources Division of the U.S. Geological Survey under the direction of Edwin E. Harris, district chief. These data represent that portion of the National Water Data System collected by the U.S. Geological Survey and cooperating State and Federal agencies in West Virginia. Beginning with the 1961 water year, streamflow records and related data have been released by the Geological Survey in annual reports on a State-boundary basis. Water-quality records beginning with the 1964 water year have been similarly released either in separate reports or in conjunction with streamflow records. These reports are for limited distribution and are designed primarily for rapid release of data shortly after the end of the water year. Records of discharge and stage of streams, and contents and stage of lakes and reservoirs are published in a series of U.S. Geological Survey water-supply papers entitled, "Surface Water. Supply of the United States." Through September 30, 1960, these water-supply papers were in an annual series and since then are in a 5-year series. Records of chemical quality, water temperatures, and suspended sediment have been published since 1941 in an annual series of water-supply papers entitled, "Quality of Surface Waters of the United States." More information is given under the headings "Publications" on pages 15 and 20.

West Virginia↗
USGS2002

Chapter A5. Processing of water samples

The National Field Manual for the Collection of Water-Quality Data (National Field Manual) describes protocols and provides guidelines for U.S. Geological Survey (USGS) personnel who collect data used to assess the quality of the Nation's surface-water and ground-water resources. This chapter addresses methods to be used in processing water samples to be analyzed for inorganic and organic chemical substances, including the bottling of composite, pumped, and bailed samples and subsamples; sample filtration; solid-phase extraction for pesticide analyses; sample preservation; and sample handling and shipping. Each chapter of the National Field Manual is published separately and revised periodically. Newly published and revised chapters will be announced on the USGS Home Page on the World Wide Web under 'New Publications of the U.S. Geological Survey.'

Techniques of Water-Resources Investigations↗
USGS2007

South Platte River Basin - Colorado, Nebraska, and Wyoming

The South Platte River Basin was one of 20 study units selected in 1991 for investigation under the U.S. Geological Survey's National Water-Quality Assessment (NAWQA) program. One of the initial tasks undertaken by the study unit team was to review the environmental setting of the basin and assemble ancillary data on natural and anthropogenic factors in the basin. The physical, chemical, and biological quality of the water in the South Platte River Basin is explicitly tied to its environmental setting. The resulting water quality is the product of the natural conditions and human factors that make up the environmental setting of the basin. This description of the environmental setting of the South Platte River Basin and its implications to the water quality will help guide the design of the South Platte NAWQA study. Natural conditions such as physiography, climate, geology, and soils affect the ambient water quality while anthropogenic factors such as water use, population, land use and water-management practices can have a pronounced effect on water quality in the basin. The relative effects of mining, urban, and agricultural land- and water-uses on water-quality constituents are not well understood. The interrelation of the surface-water and ground-water systems and the chemical and biological processes that affect the transport of constituents needs to be addressed. Interactions between biological communities and the water resources also should be considered. The NAWQA program and the South Platte River Basin study will provide information to minimize existing knowledge gaps, so that we may better understand the effect these natural conditions and human factors have on the water-quality conditions in the basin, now and in the future.

Water Resources Bulletin↗
USGS2002

Acidic deposition to streams: A geology-based method predicts their sensitivity

All water that reaches watershed systems comes directly or indirectly from precipitation. Normally, this water contains very small amounts of dissolved solids and is only slightly acidic. As a result of chemical reactions in watersheds, however, stream water generated from precipitation normally is less acidic and contains larger concentrations of dissolved solids than does the precipitation falling onto the watershed.

Environmental Science & Technology↗
USGS2000

NASQAN: The design and implementation of a large-river suspended sediment and trace element flux programme

In 1996 the US Geological Survey (USGS) began a national flux-based water quality monitoring programme in the Mississippi, Columbia, Colorado, and Rio Grande basins. Suspended sediment flux estimates for periods greater than a year are generally accurate within ??15%. Discharge and suspended sediment concentrations varied much more than chemical levels. Most trace element concentrations are not elevated except Zn and Hg in the Ohio River, and Ag, Cu, Pb, Zn, Cd, Cr, Co, Ba, Mo, Sb, Hg, and Fe in the upper Columbia River, which is impacted by mining waste. The majority (???70%) of Cu, Zn, Cr, Ni, Ba, P, As, Fe, Mn, and Al are transported by suspended sediment; Sr transported seems dominated by the dissolved phase, whereas the transport of Li and TOC seem to be divided equally between both phases.In 1996 the US Geological Survey (USGS) began a national flux-based water quality monitoring programme in the Mississippi, Columbia, Colorado, and Rio Grande basins. Suspended sediment flux estimates for periods greater than a year are generally accurate within ??15%. Discharge and suspended sediment concentrations varied much more than chemical levels. Most trace element concentrations are not elevated except Zn and Hg in the Ohio River, and Ag, Cu, Pb, Zn, Cd, Cr, Co, Ba, Mo, Sb, Hg, and Fe in the upper Columbia River, which is impacted by mining waste. The majority (???70%) of Cu, Zn, Cr, Ni, Ba, P, As, Fe, Mn, and Al are transported by suspended sediment; Sr transported seems dominated by the dissolved phase, whereas the transport of Li and TOC seem to be divided equally between both phases.

Conference Paper↗